Self-retracting imbibition chamber for cameras and method of making the same

ABSTRACT

A compact, self-retracting imbibition chamber for cameras in which the film is ejected just after exposure and passed through processing units which distribute processing fluid throughout the film unit. The apparatus includes a normally tightly coiled imbibition chamber which receives the sheet ejected from the processing rolls and retains it in a light-protected condition until it is sufficiently processed to allow it to be exposed to the light.

This invention relates to photography, and particularly to a novelcompact imbibition chamber for cameras.

Photographic processes in which the processing of the finished print iscommenced as soon as the exposure has been made have been highlydeveloped and take various forms. The processes include those in whichthe photosensitive materials must be protected from light during theprocessing procedure, as well as those in which an opacifyingcomposition is employed so that the exposed film unit may be passedthrough processing rolls and then immediately ejected into a lightedenvironment without interfering with the process. Typical of latterprocesses of this type are those involved in the preparation andprocessing of SX-70 Land film units, made and sold by PolaroidCorporation of Cambridge, Massachusetts.

For some purposes, it is desirable to limit the amount of opacifyingcomposition included in a photographic processing fluid, such as thefluid used in the SX-70 film units. When such limited amounts ofopacifier are used, it is necessary to keep the print in alight-protected environment until the processing is well advanced. Inorder to keep the size of a camera in which the film is exposed andprocessed to an acceptably compact size, it is undesirable to include animbibition chamber in the camera. The difficulty is that the film cannotbe pulled around a short radius, so that the length of the chamber wouldhave to be added to the length of the film unit. One solution to thisproblem which has been proposed is to provide a temporary imbibitionshield in the form of a plate having light protecting edges at its sidesto be used in combination with a film unit having an opaque layer on oneside and with a light-sensitive layer ejected into shielded relationshipwith an opacification device so that it can be left in a light-protectedenvironment, although outside of the camera, for any desired length oftime. In order to reduce the size of the camera, the plate is hinged tothe camera so that it can be folded back against the camera body whennot in use. Such apparatus is shown and described in U.S. Pat. No.3,369,470, issued on FEB. 20, 1968 to Rogers B. Downey for CameraApparatus and assigned to the assignee of this application. Morerestricted light protecting properties have been made available in theform of a self-retracting temporary light shield of the kind shown anddescribed in U.S. Pat. No. 3,938,167, issued on Feb. 10, 1976 to J. N.Amey and A. S. Ivester for Film Catcher, and in U.S. Pat. No. 3,940,774,issued on Feb. 24, 1976 to A. S. Ivester for Opaque Shade, both assignedto the assignee of this application. In this apparatus, a coiled,relatively opaque carbon-filled Mylar tab is provided. A film unit justpassing through the processing rolls of the camera is ejected into thecurl of the coiled tab in such a manner that it is protected by thecurled material as it is uncurled until it leaves the processing rolls,at which time it comes out of engagement with the temporary protectingtab and comes into position for removal by the user of the camera. Suchapparatus is extremely convenient in use. And the additional darkimbibition time provided is not paid for at the expense of muchadditional camera complexity or material, because the device isself-retracting into a tight coil immediately after use and thus doesnot take up much space in the camera.

The object of this invention is to attain the advantages of a longerdark imbibition period while achieving the compactness available withthe tightly coiled construction of the above-cited U.S. Pat. Nos.3,938,167 and 3,940,774.

Briefly, the above and other objects of the invention are attained by anovel imbibition chamber construction in which a film receivingimbibition chamber is provided in the form of a tightly coiled helix ofspringy opaque sheet material which has been formed with fluted sideflanges that will hold the film unit with its photosensitive face incontact with the face of the opaque sheet. The structure is initiallytightly coiled into a compact configuration but is readily extended intoa relatively flat configuration by encounter with the film unit.

The process of making an imbibition chamber in accordance with theinvention, and the apparatus and its mode of operation, will best beunderstood in the light of the following detailed description, togetherwith the accompanying drawings, of preferred embodiments of theinvention.

In the drawings,

FIG. 1 is a schematic plan sketch of a blank used in forming animbibition chamber in accordance with the invention;

FIG. 2 is a schematic plan sketch of the structure of FIG. 1 after foldshave been made;

FIG. 3 is an end view of the structure of FIG. 2;

FIG. 4 is a fragmentary schematic sketch illustrating a step in theprocess of manufacturing an imbibition chamber in accordance with theinvention;

FIG. 5 is a schematic elevational sketch illustrating another step inthe manufacture of an imbibition chamber in accordance with theinvention;

FIG. 6 is a schematic diagrammatic sketch illustrating another step inthe process of the invention;

FIG. 7 is a fragmentary cross-sectional elevational sketch, illustratingan imbibition chamber in accordance with the invention installed in acamera; and

FIG. 8 is a fragmentary perspective sketch illustrating the operation ofthe imbibition chamber in accordance with the invention.

Referring to FIG. 1, an imbibition chamber in accordance with theinvention is preferably made of a material that can be heat-cured to aflexible springy condition in which it will serve as a spring biased toreturn to the position in which it is cured. A presently preferredmaterial for this purpose is polyvinyl fluoride filled with sufficientcarbon black to make it opaque. Such a material can be purchased underthe trademark TEDLAR from the E. I. duPont de Nemours Corporation ofNewark, N.J.

The material used may be 11/2 mils in thickness. Other materials withsimilar properties may, of course, be used; for example, Mylar filledwith carbon black would also serve the purposes of the invention. Othersuitable resins, and other suitable opacifiers, will occur to thoseskilled in the art, and may be employed without departing from the scopeof the invention in its broader aspects.

As indicated in FIG. 1, the blank 1 has corners cut out to form anextending tab 2 that will be employed later to fasten the apparatus intothe camera. Cuts 3 are made for purposes to be described. The materialis then folded along the dotted lines in alignment with the cuts 3,bringing side flanges 4 over the central portion 5 of the unit 1, wherethey are creased down hard at the edges as best shown in FIG. 3.

The flanges 4 and adjacent portions of the material 5 are then fluted inany convenient manner. For example, as illustrated in FIG. 4, they maybe passed through a pair of meshing gears 6 and 7, once through thegears for each side, so that the fluting as indicated at 8 is produced.The result is best shown in FIG. 8. While FIG. 4 shows the unit 1 veryschematically as a single sheet, it will be apparent that a doublethickness goes through the rolls. The same convention is used in FIGS. 5and 6, for simplicity.

The folded unit with fluted edges formed as just described is next woundup on a mandrel. For that purpose, the end of the flanges 4 and centralportion 5 are inserted in a slot 9 formed in a rod 10, for example, aneighth inch rod or the like.

An operator then grasps a knob 11 fixed to the rod 10 and rolls the unit1 up on the rod on a suitable support, here shown as a block 12. Afterthe unit 1 is rolled up more or less loosely on the rod 10 in thisfashion, it is next cinched tightly on the rod 10 and inserted into atube, such as a brass tube or the like, illustrated at 13 in FIG. 6. Forthis purpose, the cinched roll 1 on the rod 10 is first inserted fullyinto the tube 13. The rod is then unwound slightly to release the end ofthe unit from the notch 9, so that the rod 9 may now be withdrawn fromthe tube. The unit as in the tube 13 is then cured in an oven at 300degrees for fifteen minutes.

Next, the heated unit in the tube 13 is cooled, then removed from thetube. It is now ready for installation in the camera in the mannersuggested in FIG. 7, and as more fully described in the above-cited U.S.Pat. Nos. 3,938,167 and 3,940,774. As schematicaly indicated, the camera14 is provided with a pair of processing rolls 15 and 16 between whichfilm units schematically shown at 17 are adapted to be passed forprocessing. The end 2 of the unit 1 is fixedly mounted in any convenientmanner between a pair of members 18 and 19 as suggested in FIG. 7. Ends20 of the flanges 4, which are freed by the operation of making the cuts3 as described above in connection with FIG. 1, are next secured insideof a guide member 21 serving the purpose as described in the above-citedpatents. By that arrangement, when the film unit 17 is driven outthrough the rolls, it will be caught between the flanges 4 and the mainportion 5 of the imbibition chamber and be driven into it in the mannersuggested in FIG. 8, with the end of the unit 1 remaining coiled asshown in FIG. 7 until it is flattened out by the entry of the film unit17. Once ejected from the processing rolls, the film unit will remain inthe imbibition chamber held by the flanges 4 until it is removed by theuser.

The provision of the fluted edges in the apparatus of the inventionmakes it possible to coil the unit 1 as described. The apparatus in theform shown in FIG. 2 cannot be rolled up with useful results, becausethe flanges 4 would crease and wrinkle, forming a structure that wouldstop the end of the film unit as it was inserted. The reason why rollingthe structure of FIG. 2 up would cause creases and wrinkles is that thelength of the flanges 4 is the same as the length of the underlyingstructure 5, but in the coiling process the flanges 4 are coiled about asmaller radius. There is thus a progressive stress buildup that effectsthe creasing. Fluting the sides of the unit appears to more or lessdistribute the radius between the flange and the base sheet, at least toa sufficient extent so that the undesirable effect of creasing is notencountered.

While the invention has been described with reference to the details ofa presently preferred embodiment, many changes and variations will occurto those skilled in the art upon reading this description. Such canobviously be made without departing from the scope of the invention.

Having thus described the invention, what is claimed is:
 1. Incombination with a camera having a pair of processing rolls throughwhich a film unit may be advanced for processing, a tightly coiled helixof springy opaque material having inturned film retaining flanges flutedwith adjacent regions of said material to permit coiling withoutcreasing, said coiled helix being mounted in said camera in front ofsaid rolls with portions of said flanges spread from a projecting endflap of said helix to receive the end of a film unit passing out betweensaid rolls.
 2. The apparatus of claim 1, in which said flanges areinside of the helix relative to said adjacent regions integraltherewith.
 3. Imbibition means for use with photographic apparatus ofthe type having apparatus for processing and advancing a film unittherefrom, said imbibition means comprising:a flexible structureresiliently structured to assume a configuration coiled lengthwise ofitself when in an unstressed condition, said flexible structureincluding a first section arranged to overlie at least the exposedphotosensitive surface of the film unit when said structure is uncoiled,and a pair of spaced apart flanges positioned to respectively overlieportions of the inside face of said first section immediately adjacentthe longitudinal edges of said first section and respectively connectedto the longitudinal edges of said first section so as to slidablycapture the opposed longitudinal edges of the film unit as its leadingedge is introduced into said coiled flexible structure causing saidflexible structure to progressively uncoil, said structure therebyprotecting the photosensitive surface of the film unit from actiniclight while releasably retaining the film unit therewithin, said flangesand said longitudinal edges of said first section being fluted laterallyof said structure to preclude undesirable creasing of said structurewhen in its coiled configuration.
 4. The imbibition means of claim 3wherein said spaced apart flanges respectively include corresponding endportions in non-connected relation with respect to said longitudinaledges of said first section, said non-connected flange end portionsbeing readily bendable away from said first section to accommodatereceipt and capture of the leading edge of an advancing film unitbetween said flanges and said first section.
 5. The imbibition means ofclaim 4 wherein said first section extends longitudinally beyond theends of said flanges to accommodate connection of said flexiblestructure to the camera apparatus.
 6. The apparatus of claim 4 whereinsaid flanges reside inside adjacent portions of said first section whensaid flexible structure assumes said coiled configuration.
 7. A cameraapparatus of the type comprising:a housing having a film exit slottherein; means for defining a film exposure plane within said housing;means for processing an exposed film unit and advancing the film unitfrom said housing through said film exit slot; and a flexible imbibitionstructure in fixed connection with respect to said housing andresiliently structured to assume a configuration coiled lengthwise ofitself when in an unstressed condition, said flexible structureincluding a first section arranged to overlie at least the exposedphotosensitive surface of the film unit when said structure is uncoiledas the film unit is advanced from said housing and a pair of spacedapart flanges positioned to respectively overlie portions of the insideface of said first section immediately adjacent the longitudinal edgesof said first section and respectively connected to the longitudinaledges of said first section so as to slidably capture the opposedlongitudinal edges of the film unit as its leading edge is introducedinto said coiled flexible structure during said film advancement causingsaid flexible structure to progressively uncoil, said structure therebyprotecting the photosensitive surface of the film unit from actiniclight while releasably retaining the film unit therewithin, said flangesand said longitudinal edges of said first section being fluted laterallyof said structure to preclude undesirable creasing of said structurewhen in its coiled configuration.
 8. The photographic apparatus of claim7 wherein said spaced apart flanges of said imbibition structurerespectively include corresponding end portions in non-connectedrelation with respect to said longitudinal edges of said first section,said non-connected flange end portions being readily bendable away fromsaid first section to accommodate receipt and capture of the leadingedge of an advancing film unit between said flanges and said firstsection.
 9. The photographic apparatus of claim 8 including:means forguiding and holding an advancing film unit, said guiding and holdingmeans including two spaced apart resilient guide members connectedrespectively to said non-connected flange end portions, together with athird guide member connected in fixed opposing spaced relation withrespect to said resilient guide members thereby operating to capture andguide an advancing film unit between said resilient guide members andsaid third guide member, said third guide member also connecting to saidfirst section so as to direct the advancing film unit between saidflaanges and said first section.
 10. The photographic apparatus of claim9 wherein said first section extends longitudinally beyond the ends ofsaid flanges to accommodate connection thereof to said third guidemember.
 11. The photographic apparatus of claim 7 wherein said flangesreside inside adjacent portions of said frist section when said flexiblestructure assumes said coiled configuration.